Gas-engine.



No. 858,707. 4 v 1 PATENTE JULY 2, 19o?.

l L. s. & E. .B.CUSHMAN.V

GAS ENGINE. APPLIOTION FILED JUNE 11, 1906.

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525 l 'Z5 l l j 25 E 2@ y Jrg I+ l 2,7- ,17 5 27 LESLIE S. CUSHMAN AND EYERETT B. CUSHMAN, LINCOLN, NEBRASKA.

ens-ENGINE.;

Specication of Letters Patent.

Patented July 2, 1907.

Application filed June 11,1906. Serial No. 321,260.

To all uho'm 'it may concern:

Be it known that we, LESLIE' S. CUsHMAN and `Evans'rr B. CUsHMAN, citizens of the United States,

residing at Lincoln, in the county of Lancaster and State of Nebraska, have invented a new and useful Gas-Engine, of which the following is a specification.

Thisinvention relates to internal combustion engines, and particularly to engines of the three port two i cycle type, wherein all of the' ports are under the direct con-trol of the piston.

One of the principal objects of the invention is to provide an engine which may be readily started, and

charge when a partial vacuum isl created within the` crank casing or compression. chamber, and whichwill close in order to cut ofi any direct communication be-4 tween the carbureter and the cylinder while the inlet port of the latter is opened.

A further object oi the invention is to provide a screen or ioraminous support which will retain any liquid, gasolene or other material, and prevent the passage of the same to the crank casing. f

With these and other objects in View, as will more fully hereinafter appear, thelinvention consists in certain novel features of construction and arrangement of'parts, hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the form, proportions, size and minor details o the structure maybe made without departing from the spirit or sacrificing any of the advantages of the invention.

. ln the vaccompanying drawingsz--Figure 1 is a sectionaielevation ot' a three port two cycle engine lconstructfeduinaccordance with the invention, the piston being shown at the completion of the working stroke. Fig.` v2 isla similar view' showing the piston at the com'- pletion of the lout or compression stroke. Fig. `3 is a detail perspective view of the valve detached. Figs. 4 and 5 are detail views,`illustrating modifications of the valve.

Similar numerals of reference are employed to indicate corresponding parts throughout the several figures of the drawings.

The cylinder 10 of the engine is arranged to contain a trunk piston 11 that is connected to al main crank shaft, the latter being disposed ,within a suitable crank casing 15 of the type ordinarily employed in two cycle engines. The cylinder is provided with a. feed port 16 carbureter connecting port.

and an exhaust port 17, arranged diametrically opposite each other, and the piston has a deector 18 of theusual type in order to direct the entering charge toward the upper or outer end of the cylinder.

At one side of the cylinder is a passage 22, the upper end of which communicates with the inlet port 16, and the lower end opens directly into the crank case. The outer wall of the passage 22 is formed of a plate that is bolted or otherwise secured in position, and it may be readily removed when necessary. This plate carries ears or lugs 27 to which a light disk valve 28 is pivoted, the valve being preferably formed of'a thin sheet of aluminium or other light metal to permit quick movement to open or closed positions, and said valve is acted upon by a spring 30 that tends to retain it in the closed position, shown in Fig.- 1; In the lower portion vof the passage or port 22 is a screen 31 that preferably is arranged diagonally across the passage, and through which the explosive charge is passed once when moving down into the crank casing, and again when moving from the crank casing back to the inlet port.

During the ordinary operation of the engine, the partial vacuum created in the crank casing during the out stroke of the piston will result in opening the valve 28, so that an explosive charge may flow through the port 2,5 and down through the passage 22 into the crank casing. During the working stroke of the piston, this charge will be compressed, and at the end of the working stroke the charge will flow through the port 16 into the upper end of the cylinder, while the products of combustion will pass out through the port 17. As the valve '28 is effectively closed from the beginning of the working stroke of the piston untilafter the next compression' stroke begins, it becomes impossible for any of the,

products oi combustion to pass outward through thc When starting the engine with the cylinder cold, it is usual to employ an excess quantity of gasolenc or other liquid for the first few charges, but under ordinary circumstances this liquid, or a portionof it lwill romain in purely liquid form and will 'flow down lthrough the passage 22 into the crank casing.` In the 4present instance any liquid which remains uncombincd, will be caughtby the screen 31 and will be'retaincd on thc screen until at the completion o the working stroke of thc piston, the compressed charge {lows outward throughthc passage 22, and in again passing 'through thc screen, will come into contact with the lliquid and will carry the same up to and through the iced port 16 into the cylinder.

Fig. 4 illustrates a slight modification of thc-'invention,wherein the valve 28 is connected b'y 'asprng 30 lto a stud 40 within the carburcter connection, a tension spring. being substituted for the compression spring show'n in Figs. l and 2.

Fig'. 5 illustrates a further modification in -which a plain disk valve 28EL is provided with a. stem 4l. adapted to a suitable guide 42 ai, the center of the poi-L 25, said Valve being normally hield closed by n spring 303.

The construction of the engine is much simplified by placing the carbureter 'connection directly in the J@ransfer port or'passage, and is of especial value in securing easy starting oi the engine and the oreing of Whole charges into the cylinder as soon as the work is coninieneed. Y.

We clirm- In a,three port two cycle engine, a transfenport, or passage extending between the crank case and the cylinrler inlet port, a feed port communicating with said transfer port. a suction opened valve, u light spring tending to force said valve to closed position :1nd cut nii the flow from the feed pori; into the transfer pori. :ind n screen extendingr across the transfer pori: nr a point below I'he feed pori' and cylinder inlei` pori', whereby any liquid guur Iene entering; wii'h the fresh charge bein;Y drnwn 1.o the crank easing' will he ranghi' by the screen :1nd helfl until the return ilew of the rlmrge through the transfer por( in the direction of the cylinder inler pori.

ln rosiiniony that we cliiin the foregoim.r :is our owne we hnve herein :iflxed our signatures in the presence of two Witnesses.

LESl'illG S. (IITSIIMAN. EVlllllllT B. CUSHHAN. Witnesses:

A. O. TAl'Lruz, L. W. (lUsnMAN. 

